This invention relates to the provision of connections between circuit cards and cables and, more particularly, to such provision through a backplane in a high density application.
Modern electronic systems equipment, such as for telecommunications purposes, is often constructed as modular circuit cards inserted into guide slots of mechanical card cages for engagement with connectors on a first side of a main backplane mounted to the card cage at the inward ends of the guide slots. For telecommunications equipment, the second side of the main backplane is typically provided with connectors to which cables may be attached. The main backplane provides interconnections between the connectors on its first and second sides.
In a particular application, it is required to interconnect sixteen circuit cards to 192 cables, with each circuit card having four individual connections to each cable. This results in a total of 12,288 interconnections which must be made between the connectors for the circuit cards and the connectors for the cables. Modern backplanes are composed of multiple layers, with each layer accommodating a number of circuit paths. Current backplane manufacturing imposes a set of limits on backplane designs including the thickness of the backplane and the resulting layer count. At the present time, most manufacturers can only produce a 400 mil thick backplane which would limit layer count to about sixty-four, with twenty-eight signal layers available for routing. Such a backplane is insufficient for accommodating the 12,288 interconnections required in the particular application.
Accordingly, there exists a need for a high density cross-connection system which can accommodate the desired number of interconnections.